AJR:191, November 2008 1469 MR images obtained because of postopera- tive complications are reviewed for quality and shape of the sphincter muscle, position of the rectum, shape of the sacrum, and as- sociated pelvic abnormalities related to the initial operation. Technique Pelvic MRI of patients who have under- gone surgical repair of anorectal malfor- mations is performed with high-resolution phased-array coils, such as eight-channel cardiac or torso phased-array coils. The im- aging protocol includes T1- and fast or tur- bo spin-echo T2-weighted sequences in the axial, sagittal, and coronal planes. To high- light the low-signal-intensity muscle and bowel wall against the higher-signal-intensi- ty fat and mucosa, fat saturation is not used. The surgeon is interested in the midsagittal section because it is the plane used for the operative approach. An optional sequence is oblique coronal T2-weighted images an- gulated in line with the anal canal when further clarification of the sphincter–bow- el relation is necessary. Axial T2-weighted images with fat suppression may be helpful for differentiating associated anomalies of the lower genitourinary tract. Except in the uncommon instance of postoperative anal atresia, a 24-French Foley catheter is ad- vanced through the anus into the rectum. For safety, the balloon is not inflated, and a small amount of tap water (high signal in- tensity on T2-weighted images) is instilled Postoperative Pelvic MRI of Anorectal Malformations Mohamed A. Eltomey 1 Lane F. Donnelly 2 Kathleen H. Emery 2 Marc A. Levitt 3 Alberto Peña 3 Eltomey MA, Donnelly LF, Emery KH, Levitt MA, Peña A 1 Department of Radiology and Imaging, Medical Compound, Faculty of Medicine, Tanta University, Elbahr St., Tanta, Egypt 31511. Address correspondence to M. A. Eltomey (meltomey@yahoo.com). 2 Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH. 3 Colorectal Center, Division of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH. Abdominal฀Imaging฀•฀Pictorial฀Essay AJR 2008; 191:1469–1476 0361–803X/08/1915–1469 © American Roentgen Ray Society A norectal malformations encom- pass a diverse group of con- genital malformations of the anorectum. They are frequent- ly associated with other anomalies, especial- ly of the spinal cord, vertebrae, and urogeni- tal system. Anorectal malformations occur in one in 5,000 patients and have a slight pre- dominance among boys [1, 2]. The goals of surgical correction are to promote anatomic reconstruction, establish socially acceptable bowel function, and avoid undesirable seque- lae such as fecal incontinence, urinary in- continence, and sexual dysfunction [3]. De- spite advances in the management of anorectal malformations, some patients have technical complications. Failed initial repairs of ano- rectal malformations may necessitate addi- tional surgical intervention. The indications for reoperation include rectal mislocation; strictures or acquired atresia of the rectum, vagina, or urethra; persistent, recurrent, and acquired fistulas; posterior urethral divertic- ulum; rectal prolapse; persistent cloaca; and persistent urogenital sinus in patients with persistent cloaca [4]. Pelvic MRI is a useful a tool for assess- ment of anorectal malformations before and after the initial repair [5]. Advantages in- clude excellent inherent soft-tissue contrast enhancement, multiplanar imaging capabil- ities, and lack of ionizing radiation. Disad- vantages of MRI include cost, the relatively frequent need for sedation, and lack of access to the technique in some locations. Pelvic Keywords: anorectal malformations, pelvic MRI, postoperative complications DOI:10.2214/AJR.07.3773 Received February 5, 2008; accepted after revision May 30, 2008. OBJECTIVE. Patients operated on for anorectal malformations can experience technical complications related to the initial corrective surgery. Many of these complications may ne- cessitate reoperation. Pelvic MRI is part of the evaluation to assess the position of the pulled- through bowel, the sphincter muscles, and the critical area of the posterior urethra. This ar- ticle reviews the various pelvic MRI findings in these patients. CONCLUSION. Pelvic MRI is a valuable tool in the assessment of postoperative ano- rectal malformations that may necessitate additional surgery. Eltomey et al. MRI of Anorectal Malformations Abdominal Imaging Pictorial Essay Downloaded from www.ajronline.org by 52.73.204.196 on 05/16/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved